Lead-sodium alloy



Patented Nov. 6, 1934 UNITED STAT S PATENT OFFICE 1,979,254 LEAD-SODIUMALLOY Frederick Baxter Downing, Carneys Point, and Louis S. Bake,Pennsgrove, N. 1., assignors to E. I. du Pont de 'Nemours & Company,Wilmington, DeL, a corporation of Delaware No Drawing. ApplicationJanuary 25, 1934, @erial No. 708,248

2 ctnims. (Cl. 75-1) This invention relatestoanimprovementinthe of leadalkyl compounds, higher yields of the production of lead alkyls by thereaction of alkyl lead alkyl compounds result, thepomposition is halidesupon a lead sodium alloy, and more parmore completely decomposed duringthe reaction, ticularly to the alloys employed in such process. andagglomeration of the lead particles during 5 In the process asordinarily practiced at the distillation is practically eliminatedwithout re- 00 present time a lead sodium alloy consisting of quiringthe use of a protective or dispersing agent. 90% lead and sodium isreacted with ethyl For example, when such composition of matter chlorideto form a dry reaction mass containing is employed in the production oftetra ethyl lead,

lead alkyl absorbed by finely divided lead, sodium yields of from about85% to 88% are obtained halide and a appreciable amount of undecomandthe amount .of undecomposed composition posed alloy. The lead alkyl isrecovered from the in the reaction mass at the completion of the remassby drowning in water and distilling out the action amounts to from 4% to0%, both the yield lead alkyl by means of steam. By the use of such oftetra ethyl lead and the amount of undeprocess, employing ethylchloride, yields of from composed composition depending upon the 83%, to85% of tetra ethyl lead have been obamount of magnesium present in thecomposition tained in the laborat ry. wi amounts about employed. It hasbeen found that as little as 5% to 10% of the alloy left unclecomposed.Such 0.1% of magnesium in the composition is sufliundecomposed sodiumtends to cause trouble in cient to practically eliminate allagglomeration the recovery of the alkyl lead compounds by steam of leadparticles during the distillation, which distillation, due to the factthat the undecomappears to be due to the fact that a much more posedsodium reacts with the water in which the complete reaction is obtainedwith less undecomreaction mass is drowned with the result that the posedcomposition present in the reaction mass.

metallic lead tends to form large balls, cakes or How v r, w preferablyemploy from b t 0.15%

rin whi h l w r he r c v y of h kyl l to 0.4% of magnesium as suchamount gives most 95 and are removed from the still only with greatsatisfactory results.

difficulty. In order to eliminate this balling of In order to moreclearly point out our inventhe lead, as much as possible, it has beennec tion .and illustrate the preferred mode in which sary to add aprotective agent such as, for exwe contemplate carrying the same intoeffect, the ample, thiocarbanilide or a dispersing agent such followingexamples are given:

as engine oil, or both, to the reaction mass dur- Example 1.One hundred(100) grams of a ing distillation. However, these expedients havelead-sodium alloy containing lead and 10% n t proved to be entirely satf o y s a ar e sodium by weight, equivalent to equal molecularpercentage of the distillations give trouble even proportions of the twometa1s,were r a t d with in the presence of these substances. 50 cc. ofethyl chloride in a small pressure auto- 35 An object of th p esentinventi n is t pr clave in a water bath of 75 c. for 5 hours. The vide aprocess wherein these difllculties are elimi resultant reaction mass wasdrowned in 500 cc. nated. A further object is to provide anew comofwater and the lead ethyl distilled off, with position of matter in thenature 01' 8-11 a y to be steam. The weight of lead ethyl recovered wasused in such process which composition of mat- 29.2 grams, equivalent to84.3% yield, based on 9 40 ter is substantially completely decomposeddurthe sodium.

ing the reaction and has no tendency to cause The unreacted sodium whi hwa present as balling or caking of the metallic lead. Still fursodiumhydroxide in the residue from the steam ther objects are to provide anew composition of distillation was determined by titration with matterand to advance the art. Other and further standard acid solution and theresults calculated objects will appear hereinafter. as sodium. Thisunreacted sodium was found to These objects may be accomplishedaccording be 0.51 grams or 5.1%. to our invention which comprisessubstituting for Example 2.-Onehundred (100) grams of maga smallproportion of the lead, in the lead sodium nesium bearing lead sodiumalloy consisting of alloy of the process as heretofore practiced, a89.6% lead, 10% sodium and 0.4% magnesium 505 small amount of magnesium.We have found were reacted with 50 cc. of ethyl chloride and the thatwhen amounts of magnesium varying from lead ethyl recovered in the samemanner as're- 0.05% to 1.0% of the weight of the alloy is subcited inExample 1. The yield of the lead ethyl stituted for an equivalent weightof the lead in was found to be 30.98 grams or 88.1% based on thepreparation of the alloy and such new comthe sodium.

position of matter is used in the manufacture No unreacted sodium waspresent in the reaction mass as shown by the fact that the residue fromthe steam distillation to remove the lead tetra ethyl, was neutral tophenol phthalein.

The results obtainable by varying the amounts of lead and magnesium inthe composition'are shown in the following table:

in the composition appears to be mostdesirable from a theoreticalstandpoint, we have found that, for practical purposes, the use of fromabout 0.15% to 0.2% of magnesium is preferable as larger amountsintroduce certain problems into novel alloy may of lead alkylsgenerally,

mama

the manufacture of the composition and the recovery of the alkyl leadcompounds.

While, in the above examples, we cally referred ethyl chloride, it is tobe understood .that our with similar results. Many variations andmodifications in the process as described will readily appear to thoseskilled in the art without departing from the spirit of our invention.Accordingly, the scope of. our invention is to be limited solely by theappended claims construed as broadly as is permissible in view of theprior art.

We claim:

1. A composition of matter comprising 10% sodium, 89.95% to 89.00% leadand 0.05% to 1.00% magnesium. I

2. A composition of matter comprising 10% sodium, from. about 89.85% to89.80% lead and from about 0.15% to 0.20% .magnesium.

FREDERICK BAXTER DOWNING. LOUIS s. BAKE.

have speciflto the reaction of the alloy with be employed in theproduction

